Internal combustion engines use electrically operated starters to initiate the rotation of the engine. Some high compression (HC) engines require a larger electrical and mechanical load than lower compression (LC) engines. Therefore, some HC engines use a parallel starting system having two or more starters coupled to the engine flywheel. In such systems, the mechanical and electrical loads are divided between the two starters. FIG. 1 shows a dual starter assembly 100 having two parallel starters 102a, 102b with respect to their control terminals. Each starter 102 has an electric starter motor and an engaging relay for engaging a pinion 104 with a flywheel ring gear 20 of the internal combustion engine. The starters 102 are electrically interconnected with one another such that the primary current path to the starter motors 102 is not closed until both pinions 104 are engaged or both engaging relays have engaged. Each starter 102 may also have a power relay. The power relay is switched to the primary current to the starter motor. In some starters, the power switches the primary current to the starter motor only when all the engaging relays have engaged.
When a user initiates the starting operations, if the first starter 102a has a malfunction, the second starter 102b will receive a signal from the first starter 102 indicating that the first starter 102a has a malfunction and the second starter will not attempt to turn over the engine by itself. This also occurs if the second starter 102b has the malfunction (i.e., the first starter 102a will not attempt to turn over the engine by itself). Therefore, in dual starter systems 100, both starters 102 need to be individually operational before the system 100 as a whole can be operational.
It is rare for both starters to fail simultaneously so, in situations where one of the starters 102 becomes inoperable, it becomes time consuming for a technician to determine which of the two starters 102 has failed, and consequently the technician often replaces both of the starters (even though one of them may be fully functional). This leads to higher cost of repairs and wasted time and other resources.